Canning apparatus has been developed to insert food products such as meat, vegetables and the like into containers. The food product is most often cut or sliced into smaller pieces such as cubes prior to the insertion of the food product into the container. One of the benefits of the cube like pieces is that it is easier to produce a uniformly sized portion to be inserted into the container. The sized portion may relate to the volume or the weight of the food product.
Typically the canning or filling apparatus has a basin which receives the cubed pieces in bulk. The basin has depending sleeves that have a cross section that match the cross section of the container in which the food product is to be inserted. Mounted above the depending sleeves are upper plungers. The plungers are movable downward to force and compress the food product into the depending sleeves. Generally there are movable inserts that are movable between alignment with the depending sleeves and the containers to be filled. The inserts are open ended and receive a lower plunger when in alignment with the depending sleeves. The lower plunger is in opposition to the upper plunger and thus the food product is compressed in the depending sleeve and the insert by the counter action of the upper and lower plungers. The upper plungers are urged downward such as by cam action in conjunction with biasing springs to provide a yieldable compressive force. When the food product is compressed, a knife enters between the depending sleeve and the insert to sever the desired portion that has been forced into the insert. The insert is then moved into alignment with the container and a tamper ejects the food product from the insert into the container. A typical machine as generally described above is disclosed in U.S. Pat. No. 5,041,297, which is incorporated in full herein by reference.
The basin which receives the food product in bulk has baffles or other apparatus to aid in directing the food into the depending sleeves. Even with this arrangement, a portion of the food product will be above and surround the top opening to the sleeves. As the upper plunger descends, cubes of the food product are often caught between the edges of the upper plunger and the sleeve. This results in the tearing or shredding of the food product which is undesirable. Also, depending on the food product being processed, a cube caught between the upper plunger and the sleeve edge will cause a jamming or a partial jamming of the upper plunger. Also, every different product has a different coefficient of friction which changes the amount of force necessary to push the product down through the sleeve. Each of these conditions affects the compressive force applied by the upper plunger to the food product received in the sleeves and inserts. The variance in the compressive force affects the compaction of the food product in the sleeve and insert which will cause a variance in the density of the food product and thus cause a variance in the weight for a given volume of the food product portion.
The upper plungers, as previously mentioned, are yieldably biased downward, such as by cam action in conjunction with a biasing spring to force the upper plungers downward. The cam action in conjunction with the spring thus only controls the force that the upper plunger will exert in the downward direction at the top of the column of product and does not control the actual compressive force applied to the food product being sized in the insert.